Carbon (δ13C) and Nitrogen (δ15N) Stable Isotope Signatures in Bat Fur Indicate Swarming Sites Have Catchment Areas for Bats from Different Summering Areas

Migratory patterns of bats are not well understood and traditional methods to study this, like capture-mark-recapture, may not provide enough detail unless there are many records. Stable isotope profiles of many animal species have been used to make inferences about migration. Each year Myotis lucifugus and M. septentrionalis migrate from summering roosts to swarming caves and mines in the fall, but the pattern of movement between them is not well understood. In this study, fur δ¹³C and δ¹⁵N values of 305 M. lucifugus and 200 M. septentrionalis were analyzed to make inferences about migration patterns between summering areas and swarming sites in Nova Scotia, Canada. We expected that there would be greater variability in δ¹³C and δ¹⁵N among individuals at swarming sites because it was believed that these sites are used by individuals originating from many summering areas. There was extensive overlap in the standard ellipse area, corrected for small sample sizes (SEA_c), of bats at swarming sites and much less overlap in SEA_c among groups sampled at summering areas. Meaningful inference could not be made on M. septentrionalis because their low variation in SEAc may have been the result of sampling only 3 summering areas. However, for M. lucifugus, swarming sites had larger SEA_c than summering areas and predictive discriminant analysis assigned swarming bats to multiple summering areas, supporting the contention that swarming bats are mixed aggregations of bats from several summering areas. Together, these data support the contention that swarming sites have catchment areas for bats from multiple summering areas and it is likely that the catchment areas for swarming sites overlap. These data suggest that δ¹³C and δ¹⁵N profiling of bat fur offer some potential to make inferences about regional migration in bats.     

Genetic connectivity among swarming sites in the wide ranging and recently declining little brown bat (Myotis lucifugus)

Characterizing movement dynamics and spatial aspects of gene flow within a species permits inference on population structuring. As patterns of structuring are products of historical and current demographics and gene flow, assessment of structure through time can yield an understanding of evolutionary dynamics acting on populations that are necessary to inform management. Recent dramatic population declines in hibernating bats in eastern North America from white‐nose syndrome have prompted the need for information on movement dynamics for multiple bat species. We characterized population genetic structure of the little brown bat, Myotis lucifugus, at swarming sites in southeastern Canada using 9 nuclear microsatellites and a 292‐bp region of the mitochondrial genome. Analyses of F_ST, Φ_ST, and Bayesian clustering (STRUCTURE) found weak levels of genetic structure among swarming sites for the nuclear and mitochondrial genome (Global F_ST = 0.001, P < 0.05, Global Φ_ST = 0.045, P < 0.01, STRUCTURE K = 1) suggesting high contemporary gene flow. Hierarchical AMOVA also suggests little structuring at a regional (provincial) level. Metrics of nuclear genetic structure were not found to differ between males and females suggesting weak asymmetries in gene flow between the sexes. However, a greater degree of mitochondrial structuring does support male‐biased dispersal long term. Demographic analyses were consistent with past population growth and suggest a population expansion occurred from approximately 1250 to 12,500 BP, following Pleistocene deglaciation in the region. Our study suggests high gene flow and thus a high degree of connectivity among bats that visit swarming sites whereby mainland areas of the region may be best considered as one large gene pool for management and conservation.     

Genetic structure in a swarming brown long-eared bat (<Emphasis Type="Italic">Plecotus auritus</Emphasis>) population: evidence for mating at swarming sites

Plecotus auritus, a small, gleaning bat species, lives in small, isolated summer colonies in which both males and females show a high degree of natal philopatry. Despite this, colonies have high gene diversities and low inbreeding coefficients. It has been suggested that inbreeding is avoided because mating occurs during autumnal and spring swarming at hibernation sites. We tested this hypothesis by comparing microsatellite profiles, based on eight loci, of bats from six summer colonies and two swarming sites they were known to visit from radiotelemetry studies. We found high gene diversities (H _s = 0.77) at both swarming sites and summer colonies which were not statistically different. There was no detectable isolation by distance and F_ST was low (0.001). Together, these results suggest high gene flow between sites. Despite this, there was small but significant genetic differentiation amongst summer colonies and between summer colonies and the primary swarming site. We suggest that swarming is important for gene flow and for maintaining genetic diversity in this highly philopatric species and discuss possible reasons for the genetic differentiation observed. The identification and protection of swarming sites should be a major conservation priority for this and other temperate bat species.     

Lactate Dehydrogenase Isozymes in the Tissues of Hibernating Bats (Chiroptera)

A comparative electrophoretic assay of lactate dehydrogenase (EC 1.1.1.27) isozymes has been carried out in the homogenates of the tissues of cardiac and skeletal muscles, liver, kidneys and lungs of five species of hibernating bats of the order Chiroptera: the northern bat Eptesicus nilssonii Keyserling and Blasius, the brown long-eared bat Plecotus auritus L., Brandt’s bat Myotis brandtii Eversmann, Daubenton’s bat Myotis daubentonii Kuhl, and the whiskered bat Myotis mystacinus Kuhl, which live in Karelia near the northern border of their distribution area. High contents of aerobic lactate dehydrogenase 1 and lactate dehydrogenase 2 isozymes have been detected in the skeletal muscle of the studied bats. The lactate dehydrogenase isozyme spectra of the tissues of kidneys and skeletal muscles from the smaller representatives of bats (the whiskered and Brandt’s bats) contained the highest content of H subunits among the studied species. In contrast, the predominance of M subunits has been revealed in the lactate dehydrogenase isozyme spectra of the kidneys of the northern and the brown long-eared bats. The discovered interspecies differences are discussed in the context of the adaptation of bats to hibernation.     

Enhanced Passive Bat Rabies Surveillance in Indigenous Bat Species from Germany - A Retrospective Study

In Germany, rabies in bats is a notifiable zoonotic disease, which is caused by European bat lyssaviruses type 1 and 2 (EBLV-1 and 2), and the recently discovered new lyssavirus species Bokeloh bat lyssavirus (BBLV). As the understanding of bat rabies in insectivorous bat species is limited, in addition to routine bat rabies diagnosis, an enhanced passive surveillance study, i.e. the retrospective investigation of dead bats that had not been tested for rabies, was initiated in 1998 to study the distribution, abundance and epidemiology of lyssavirus infections in bats from Germany. A total number of 5478 individuals representing 21 bat species within two families were included in this study. The Noctule bat (Nyctalus noctula) and the Common pipistrelle (Pipistrellus pipistrellus) represented the most specimens submitted. Of all investigated bats, 1.17% tested positive for lyssaviruses using the fluorescent antibody test (FAT). The vast majority of positive cases was identified as EBLV-1, predominately associated with the Serotine bat (Eptesicus serotinus). However, rabies cases in other species, i.e. Nathusius'' pipistrelle bat (Pipistrellus nathusii), P. pipistrellus and Brown long-eared bat (Plecotus auritus) were also characterized as EBLV-1. In contrast, EBLV-2 was isolated from three Daubenton''s bats (Myotis daubentonii). These three cases contribute significantly to the understanding of EBLV-2 infections in Germany as only one case had been reported prior to this study. This enhanced passive surveillance indicated that besides known reservoir species, further bat species are affected by lyssavirus infections. Given the increasing diversity of lyssaviruses and bats as reservoir host species worldwide, lyssavirus positive specimens, i.e. both bat and virus need to be confirmed by molecular techniques.     

Population genetic structure and gene flow in a gleaning bat,Plecotus auritus

During summer the brown long-eared bat Plecotus auritus (Vespertilionidae) forms stable colonies, comprised of both adult females and males and young of the year. A long-term ringing study conducted in north-east Scotland has established that little movement occurs among colonies and that both sexes are recruited into their natal colony. The aim of the present study was to investigate, using microsatellite DNA markers, if genetic structure within the population reflects the spatial structure indicated by ringing. Inter-colony F_ST estimates obtained for all colony members, and for females and males separately, were low (0.019, 0.026 and 0.011, respectively), but all values differed significantly from zero. These data indicate high gene flow between colonies, although some coancestry among colony members is evident in both sexes. On combining the ringing and genetic data, it is concluded that gene flow occurs via extra-colony copulation, rather than natal dispersal, and that each colony behaves as a distinct subpopulation. Microgeographical genetic isolation by distance was demonstrated for, to our knowledge, the first time in a bat species, and found to be apparent both across the entire study area and along one river valley. The results suggest that extensive macrogeographical population genetic structure may be evident across the species'' range.     

Seasonal Shifts in Nocturnal Habitat Use by Coastal Bat Species

Sensitivity of bats to land use change depends on their foraging ecology, which varies among species based on ecomorphological traits. Additionally, because prey availability, vegetative clutter, and temperature change throughout the year, some species may display seasonal shifts in their nocturnal habitat use. In the Coastal Plain of South Carolina, USA, the northern long-eared bat (Myotis septentrionalis), southeastern myotis (Myotis austroriparius), tri-colored bat (Perimyotis subflavus), and northern yellow bat (Lasiurus intermedius) are species of conservation concern that are threatened by habitat loss. Our objective was to identify characteristics of habitat used by these species during their nightly active period and compare use between summer and winter. We conducted acoustic surveys at 125 sites during May–August and at 121 of the same 125 sites December–March 2018 and 2019 in upland forests, bottomland forests, fields, ponds, and salt marsh and used occupancy models to assess habitat use. The northern long-eared bat and southeastern myotis (i.e., myotis bats) used sites that were closer to hardwood stands, pine stands, and fresh water year-round. We did not identify any strong predictors of tri-colored bat habitat use in summer, but during winter they used bottomland forests, fields, and ponds more than salt marsh and upland forests. During summer and winter, northern yellow bats used sites close to fresh water and salt marsh. Additionally, during summer they used fields, ponds, and salt marsh more than upland and bottomland forests, but in winter they used bottomland forests, fields, and ponds more than upland forest and salt marsh. Our results highlight important land cover types for bats in this area (e.g., bottomland forests, ponds, and salt marsh), and that habitat use changes between seasons. Accounting for and understanding how habitat use changes throughout the year will inform managers about how critical habitat features may vary in their importance to bats throughout the year. © 2021 The Wildlife Society.     

Predictive Occurrence Models for Bat Species in California

Abstract: The ability to accurately predict the potential occurrence of species of management concern is useful for wildlife managers, particularly for those whose management activities involve large areas where sampling is difficult due to logistical or financial constraints. During the summers of 2002 and 2003, we used mist nets to capture bats (Myotis yumanensis, M. californicus, M. evotis, M. thysanodes, Eptesicus fuscus, Lasionycteris noctivagans, Tadarida brasiliensis, Antrozous pallidus, Lasiurus borealis, and Lasiurus cinereus) in Whiskeytown National Recreation Area in north-central California, USA. We used landscape-scale variables, logistic regression, and Akaike's Information Criterion (AIC_c) to model species distributions and produce spatially discerning predictive occurrence maps. We developed a priori models that we used to determine which landscape-scale variables best discriminated between capture sites and non-capture sites. The odds of capturing a bat were 3.3 greater when total edge increased by 10,000 m, whereas for Yuma myotis (Myotis yumanensis), the odds of predicting presence were 0.2 greater when distance to lakes and ponds decreased by 2,000 m. Elevation was important in predicting the distribution of silver-haired bats (Lasionycteris noctivagans) and big brown bats (Eptesicus fuscus). Increasing elevation by 400 m decreased the odds of capturing a silver-haired bat by 0.1 and a big brown bat by 0.4. Classification accuracy for our models ranged from 80.9% for all bat species combined to 72.3% for Yuma myotis and silver-haired bats. Predictive occurrence models can be valuable to bat conservation efforts because they provide spatial data important for evaluating the effects of management activities on species distributions.     

Effects of Hierarchical Roost Removal on Northern Long-Eared Bat (Myotis septentrionalis) Maternity Colonies

Forest roosting bats use a variety of ephemeral roosts such as snags and declining live trees. Although conservation of summer maternity habitat is considered critical for forest-roosting bats, bat response to roost loss still is poorly understood. To address this, we monitored 3 northern long-eared bat (Myotis septentrionalis) maternity colonies on Fort Knox Military Reservation, Kentucky, USA, before and after targeted roost removal during the dormant season when bats were hibernating in caves. We used 2 treatments: removal of a single highly used (primary) roost and removal of 24% of less used (secondary) roosts, and an un-manipulated control. Neither treatment altered the number of roosts used by individual bats, but secondary roost removal doubled the distances moved between sequentially used roosts. However, overall space use by and location of colonies was similar pre- and post-treatment. Patterns of roost use before and after removal treatments also were similar but bats maintained closer social connections after our treatments. Roost height, diameter at breast height, percent canopy openness, and roost species composition were similar pre- and post-treatment. We detected differences in the distribution of roosts among decay stages and crown classes pre- and post-roost removal, but this may have been a result of temperature differences between treatment years. Our results suggest that loss of a primary roost or ≤ 20% of secondary roosts in the dormant season may not cause northern long-eared bats to abandon roosting areas or substantially alter some roosting behaviors in the following active season when tree-roosts are used. Critically, tolerance limits to roost loss may be dependent upon local forest conditions, and continued research on this topic will be necessary for conservation of the northern long-eared bat across its range.     

Genetic structuring of northern myotis (Myotis septentrionalis) at multiple spatial scales

Although groups of bats may be genetically distinguishable at large spatial scales, the effects of forest disturbances, particularly permanent land use conversions on fine-scale population structure and gene flow of summer aggregations of philopatric bat species are less clear. We genotyped and analyzed variation at 10 nuclear DNA microsatellite markers in 182 individuals of the forest-dwelling northern myotis (Myotis septentrionalis) at multiple spatial scales, from within first-order watersheds scaling up to larger regional areas in West Virginia and New York. Our results indicate that groups of northern myotis were genetically indistinguishable at any spatial scale we considered, and the collective population maintained high genetic diversity. It is likely that the ability to migrate, exploit small forest patches, and use networks of mating sites located throughout the Appalachian Mountains, Interior Highlands, and elsewhere in the hibernation range have allowed northern myotis to maintain high genetic diversity and gene flow regardless of forest disturbances at local and regional spatial scales. A consequence of maintaining high gene flow might be the potential to minimize genetic founder effects following population declines caused currently by the enzootic White-nose Syndrome.     

The Resistance of a North American Bat Species (Eptesicus fuscus) to White-Nose Syndrome (WNS)

White-nose Syndrome (WNS) is the primary cause of over-winter mortality for little brown (Myotis lucifugus), northern (Myotis septentrionalis), and tricolored (Perimyotis subflavus) bats, and is due to cutaneous infection with the fungus Pseudogymnoascus (Geomyces) destructans (Pd). Cutaneous infection with P. destructans disrupts torpor patterns, which is thought to lead to a premature depletion of body fat reserve. Field studies were conducted at 3 WNS-affected hibernation sites to determine if big brown bats (Eptesicus fuscus) are resistant to Pd. Radio telemetry studies were conducted during 2 winters to determine the torpor patterns of 23 free-ranging E. fuscus hibernating at a site where Pd occurs. The body fat contents of free-ranging E. fuscus and M. lucifugus during hibernation at 2 different WNS-affected sites were also determined. The numbers of bats hibernating at the same site was determined during both: a) 4–7 years prior to the arrival of Pd, and, b) 2–3 years after it first appeared at this site. The torpor bouts of big brown bats hibernating at a WNS-affected site were not significantly different in length from those previously reported for this species. The mean body fat content of E. fuscus in February was nearly twice that of M. lucifugus hibernating at the same WNS-affected sites during this month. The number of M. lucifugus hibernating at one site decreased by 99.6% after P. destructans first appeared, whereas the number of E. fuscus hibernating there actually increased by 43% during the same period. None of the E. fuscus collected during this study had any visible fungal growth or lesions on their skin, whereas virtually all the M. lucifugus collected had visible fungal growth on their wings, muzzle, and ears. These findings indicate that big brown bats are resistant to WNS.     

Influences of Landscape Features on Bat Activity in North Dakota

Land conversion and modification threatens many wildlife and plant species in the northern Great Plains, including bats. Our objective was to assess the association of bat species with landscape features in the northern Great Plains of North Dakota, USA, taking the first step towards understanding the habitat needs of bats in this region. We examined patterns of bat activity across different landscapes, identified those landscape features associated with high levels of bat activity, and determined which specific land features (i.e., vegetation and water types) were most commonly associated with each bat species. We used passive acoustic monitoring to measure bat activity at sites across North Dakota, and assessed detailed land characteristics at each site. We used nonmetric multidimensional scaling and multivariate regression tree analysis to examine relationships between bat activity and landscape variables. Bat foraging activity was influenced by structural landscape characteristics and the availability of specific water resources. High levels of bat activity were associated with riparian forested areas of varying structural complexity, ponds, and, to a lesser extent, open riparian lands. Individual bat species were influenced by land type and water resources differently. We identified big brown bats (Eptesicus fuscus) and little brown bats (Myotis lucifugus) as indicators of open riparian and pond landscapes, respectively. These results highlight the importance of prairie riparian landscapes and maintaining heterogeneity across the landscape for conservation and management of bat communities. Further, we identified ponds as an important landscape feature for little brown bats, a species of conservation concern, indicating that this specific feature should be a focus of conservation efforts on prairie wetlands. © 2019 The Wildlife Society.     

Evolution of opsin genes reveals a functional role of vision in the echolocating little brown bat (Myotis lucifugus)

Echolocating bats are able to orientate, navigate and forage without visual cues. To probe the role of vision in bats, we studied the visual opsin genes from the echolocating little brown bat (Myotis lucifugus). Short-wavelength sensitive (SWS1) opsin, middle/long-wavelength sensitive (M/LWS) opsin and rhodopsin cDNA sequences were identified from the Ensembl database and validated by the sequencing of genomic DNA. We retrieved the published orthologous genes from eleven additional representative species of mammals from GenBank and conducted an evolutionary analysis. We found that the M/LWS opsin and rhodopsin genes were both under strong purifying selection, whereas the SWS1 opsin gene has undergone positive selection at two amino acid sites and one lineage, though the main evolutionary force is still purifying selection. Two-ratio model of the SWS1 opsin gene revealed that the ω ratio for the little brown bat lineage was nearly three times lower than the background ratio, suggesting a much stronger functional constraint. Our relative rate tests show the little brown bat has a lower nonsynonymous substitution rate than those in other mammals (on average 32% lower) for the SWS1 opsin gene. However, no such significant differences were detected for the M/LWS opsin and rhodopsin genes. The results of the relative ratio tests are consistent with that of tests for selection, showing a history of purifying selection on the little brown bat opsin genes. These findings suggest a functional role of vision in the little brown bat despite being nocturnal and using echolocation. We speculate that this echolocating bat may be able to use visual cues to orientate, navigate and forage at night, to discriminate color under moonlight and starlight conditions, or to avoid predation by diurnal raptors.     

Development of conserved microsatellite markers of high cross-species utility in bat species (Vespertilionidae, Chiroptera, Mammalia)

Comparative ecological and behavioural studies of the widespread and diverse Vespertilionidae, which comprise almost 400 of the 1100 bat species, have been limited by the availability of markers. The potential of new methods for developing conserved microsatellite markers that possess enhanced cross-species utility has recently been illustrated in studies of birds. We have applied these methods to develop enhanced microsatellite markers for vespertilionid bats, in particular for the genus Myotis (103 species). We compared published bat microsatellites with their homologues in the genome sequence of the little brown bat, Myotis lucifugus, to create consensus sequences that were used to design candidate primer sets. Primer sets were then tested for amplification and polymorphism in 22 species of bat from nine of the largest families (including 11 Vespertilionidae). Of 46 loci tested, 33 were polymorphic, on average, in each of seven Myotis species tested, 20 in each of four species in other vespertilionid genera, and two in 11 nonvespertilionid species.     

Hybridization Hotspots at Bat Swarming Sites

During late summer and early autumn in temperate zones of the Northern Hemisphere, thousands of bats gather at caves, mainly for the purpose of mating. We demonstrated that this swarming behavior most probably leads not only to breeding among bats of the same species but also interbreeding between different species. Using 14 nuclear microsatellites and three different methods (the Bayesian assignment approaches of STRUCTURE and NEWHYBRIDS and a principal coordinate analysis of pairwise genetic distances), we analyzed 375 individuals belonging to three species of whiskered bats (genus Myotis) at swarming sites across their sympatric range in southern Poland. The overall hybridization rate varied from 3.2 to 7.2%. At the species level, depending on the method used, these values ranged from 2.1–4.6% in M. mystacinus and 3.0–3.7% in M. brandtii to 6.5–30.4% in M. alcathoe. Hybrids occurred in about half of the caves we studied. In all three species, the sex ratio of hybrids was biased towards males but the observed differences did not differ statistically from those noted at the population level. In our opinion, factors leading to the formation of these admixed individuals and their relatively high frequency are: i) swarming behaviour at swarming sites, where high numbers of bats belonging to several species meet; ii) male-biased sex ratio during the swarming period; iii) the fact that all these bats are generally polygynous. The highly different population sizes of different species at swarming sites may also play some role. Swarming sites may represent unique hybrid hotspots, which, as there are at least 2,000 caves in the Polish Carpathians alone, may occur on a massive scale not previously observed for any group of mammal species in the wild. Evidently, these sites should be treated as focal points for the conservation of biodiversity and evolutionary processes.     

High gene diversity at swarming sites suggest hot spots for gene flow in the endangered Bechstein's bat

Our study shows that endangered Bechstein'sbats utilise distinct habitats at differentstages of their reproductive cycle, a findingthat has implications how habitat should beselected for preservation. Using nuclear andmitochondrial microsatellite DNA markers wecompared gene diversity of Bechstein's batswithin breeding colonies and at potentialmating sites. Bechstein's bat is one of themost threatened European bat species. Duringsummer it depends largely on mature deciduousforests. Females exhibit strict natalphilopatry. They form demographicallyindependent breeding colonies comprisingmaternally closely related bats. Males aresolitary. Like other temperate bats,Bechstein's bats swarm at the end of summer infront of caves. Because the sexes meet there,such swarming sites are potentially importantfor gene flow. Our genetic analyses reveal thatswarming sites have greater mitochondrial DNAgene diversity than colonies. Furthermore,field data on the phenology and reproductivestatus of several hundred individuals suggestthat Bechstein's bats mate during swarming. Incombination our field and genetic data showthat swarming sites provide the opportunity forgene flow among bats originating from differentcolonies. Therefore, we suggest that swarmingsites should be strictly protected to maintainthe observed high levels of gene flow amongcolonies.     

Population stock structure of leatherback turtles (Dermochelys coriacea) in the Atlantic revealed using mtDNA and microsatellite markers

This study presents a comprehensive genetic analysis of stock structure for leatherback turtles (Dermochelys coriacea), combining 17 microsatellite loci and 763 bp of the mtDNA control region. Recently discovered eastern Atlantic nesting populations of this critically endangered species were absent in a previous survey that found little ocean-wide mtDNA variation. We added rookeries in West Africa and Brazil and generated longer sequences for previously analyzed samples. A total of 1,417 individuals were sampled from nine nesting sites in the Atlantic and SW Indian Ocean. We detected additional mtDNA variation with the longer sequences, identifying ten polymorphic sites that resolved a total of ten haplotypes, including three new variants of haplotypes previously described by shorter sequences. Population differentiation was substantial between all but two adjacent rookery pairs, and F _ST values ranged from 0.034 to 0.676 and 0.004 to 0.205 for mtDNA and microsatellite data respectively, suggesting that male-mediated gene flow is not as widespread as previously assumed. We detected weak (F _ST = 0.008 and 0.006) but significant differentiation with microsatellites between the two population pairs that were indistinguishable with mtDNA data. POWSIM analysis showed that our mtDNA marker had very low statistical power to detect weak structure (F _ST < 0.005), while our microsatellite marker array had high power. We conclude that the weak differentiation detected with microsatellites reflects a fine scale level of demographic independence that warrants recognition, and that all nine of the nesting colonies should be considered as demographically independent populations for conservation. Our findings illustrate the importance of evaluating the power of specific genetic markers to detect structure in order to correctly identify the appropriate population units to conserve.     

Behavioural flexibility: the little brown bat, Myotis lucifugus, and the northern long-eared bat,M. septentrionalis , both glean and hawk prey

We present behavioural data demonstrating that the little brown bat, Myotis lucifugus, and the northern long-eared bat, M. septentrionalis, can glean prey from surfaces and take prey on the wing. Our data were collected in a large outdoor flight room mimicking a cluttered environment. We compared and analysed flight behaviours and echolocation calls used by each species of bat when aerial hawking and gleaning. Our results challenge the traditional labelling ofM. lucifugus as an obligate aerial-hawking species and show that M. septentrionalis, which is often cited as a gleaning species, can capture airborne prey. As has been shown in previous studies, prey-generated acoustic cues were necessary and sufficient for the detection and localization of perched prey. We argue that the broadband, high-frequency, downward-sweeping, frequency-modulated calls used by some bats when gleaning prey from complex surfaces resolve targets from background. First, because calls of lower frequency and narrower bandwidth are sufficient for assessing a surface before landing, and second, because there are few, if any, simple surfaces in nature from which substrate-gleaning behaviours in wild bats would be expected. Copyright 2003 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.     

Next Generation Sequencing of Fecal DNA Reveals the Dietary Diversity of the Widespread Insectivorous Predator Daubenton’s Bat (Myotis daubentonii) in Southwestern Finland

Understanding predator-prey dynamics is a fundamental task in the evaluation of the adaptive capacities of species. However, direct observations or morphological identification of fecal remains do not offer an effective way to study the dietary ecology of elusive species, such as nocturnal insectivorous bats. However, recent advances in molecular techniques have opened a new method for identifying prey species from fecal samples. In this study, we amplified species-specific mitochondrial COI fragments from fecal DNA extractions from 34 individual Daubenton’s bats (Myotis daubentonii) collected between 2008 and 2010 from southwestern Finland. Altogether, 128 different species of prey were identified based on a comprehensive local DNA reference library. In our study area, Daubenton’s bats feed most frequently on insects of the orders Diptera (found in the diet of 94% individuals), Trichoptera (69%) and Lepidoptera (63%). The most frequent dipteran family in the diet was Chironomidae, which was found in 31 of 34 individuals. Most common prey species were chironomids Microtendipes pedellus (found in 50% of bats), Glyptotendipes cauliginellus (44%), and Procladius ferrugineus (41%). For the first time, an accurate species level list of the diet of the insectivorous Daubenton’s bat (Myotis daubentonii) in Finland is presented. We report a generally applicable method for describing the arthropod diet of vertebrate predators. We compare public databases to a national database to highlight the importance of a local reference database.     

Susceptibility and Pathogenesis of Little Brown Bats (Myotis lucifugus) to Heterologous and Homologous Rabies Viruses

Rabies virus (RABV) maintenance in bats is not well understood. Big brown bats (Eptesicus fuscus), little brown bats (Myotis lucifugus), and Mexican free-tailed bats (Tadarida brasiliensis) are the most common bats species in the United States. These colonial bat species also have the most frequent contact with humans and domestic animals. However, the silver-haired bat (Lasionycteris noctivagans) RABV is associated with the majority of human rabies virus infections in the United States and Canada. This is of interest because silver-haired bats are more solitary bats with infrequent human interaction. Our goal was to determine the likelihood of a colonial bat species becoming infected with and transmitting a heterologous RABV. To ascertain the potential of heterologous RABV infection in colonial bat species, little brown bats were inoculated with a homologous RABV or one of two heterologous RABVs. Additionally, to determine if the route of exposure influenced the disease process, bats were inoculated either intramuscularly (i.m.) or subcutaneously (s.c.) with a homologous or heterologous RABV. Our results demonstrate that intramuscular inoculation results in a more rapid progression of disease onset, whereas the incubation time in bats inoculated s.c. is significantly longer. Additionally, cross protection was not consistently achieved in bats previously inoculated with a heterologous RABV following a challenge with a homologous RABV 6 months later. Finally, bats that developed rabies following s.c. inoculation were significantly more likely to shed virus in their saliva and demonstrated increased viral dissemination. In summary, bats inoculated via the s.c. route are more likely to shed virus, thus increasing the likelihood of transmission.